Corrosion Protection of Nano-Silica Powder Coatingon Artificial Seawater

2021 ◽  
Vol 904 ◽  
pp. 519-524
Author(s):  
Gui Yun Zhang ◽  
Yong Wang ◽  
Tian Wei Zhang ◽  
Chen Yu Zhao

Sea water resources are extensive and can be used to extinguish fires, but their corrosiveness is a major problem. Using the method of electrochemical workstation, the electrochemical corrosion behavior of aluminum sheet in artificial sea water solution and silica-coated artificial seawater was studied; by analyzing the surface morphology, polarization curve and electrochemical impedance spectroscopy, the electrochemical corrosion behavior of aluminum sheets under different immersion times and different immersion media is obtained. The conclusion is that the coating of nanosilica powder has a certain corrosion protection effect on artificial seawater.

2012 ◽  
Vol 189 ◽  
pp. 36-39
Author(s):  
Hai Jiao Yang ◽  
Sheng Tao Zhang ◽  
Lei Zhang

The corrosion behavior of copper in halide solutions was investigated by cyclic voltammetry, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). On this basis, the mechanism of electrochemical corrosion behavior of Cu in halide solutions has been analyzed. The study explores the corrosive effect of the halide ions on copper materials and provides a theoretical basis for the inhibition of halide ions on the corrosion of copper materials.


2014 ◽  
Vol 61 (3) ◽  
pp. 146-152 ◽  
Author(s):  
Ali Ehsani ◽  
Mohammad Ghasem Mahjani ◽  
Maryam Nasseri ◽  
Majid Jafarian

Purpose – The purpose of this paper was to investigate the anti-corrosion behavior of polypyrrole (PPy) films in different states and presence of alumina nanoparticles synthesized by galvanostatic electropolymerization on stainless steel (SS) electrodes in an artificial seawater solution using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). Design/methodology/approach – The electrochemical measurements were used to examine the effects of PPy and its nanocomposite on the corrosion behavior of SS type 316L in artificial seawater. A standard electrochemical cell with three electrodes was used for the measurements. The electrochemical response of the coated electrodes in the doped and the undoped state was compared with that of a bare electrode. Corrosion rate information was obtained by the Tafel extrapolation method, where the intersection point of a cathodic and an anodic polarization curve provides both the corrosion potential and the corrosion current. EIS measurements confirmed the potentiodynamic and open circuit potential (OCP) results. The microstructure of the obtained films was investigated by scanning electron microscopy. Findings – The results showed that the coated polymer films shifted the electrode potential toward more positive potentials, but this shift did not lead to passivation. However, a notable synergy was observed between PPy undoped film, oxygen reduction and iron dissolution. The potential of the SS remained in the active dissolution region, and it was not possible to produce a passive oxide layer in this region. PPy separates the metal dissolution process from the oxygen reduction process. This would prevent the local pH increase at the metal surface and subsequent delamination. The polarization curves, EOCP and impedance measurements showed that PPy undoped/Al2O3 layers show promise as good candidates for the corrosion protection of reactive metals. Originality/value – This paper presents that electrodes coated with undoped PPy synthesized in the presence of dodecyl sulfate anions and Al2O3 nanoparticles offered a noticeable enhancement of protection against corrosion processes.


2018 ◽  
Vol 69 (1) ◽  
pp. 86-90 ◽  
Author(s):  
Ioana Arina Gherghescu ◽  
Daniela Ionita ◽  
Sorin Ciuca ◽  
Ruxandra Elena Dumitrescu

This paper presents some electrochemical impedance spectroscopy research results concerning the corrosion resistance of a shape memory Ni50Ti48Nb2 alloy. This one was previously studied by SEM and DSC [1,2] but some new research features had to be made clear in order to be able to explain its electrochemical corrosion behavior. The chemical composition Ni50Ti48Nb2 was chosen in order to obtain a shape memory alloy having a wider hysteresis than equiatomic NiTi, for the purpose of achieving a better thermomechanical stability. Cryogenic applications are aimed. After processing the cast ingot, two samples, S1 and S2, were further annealed at 800�C/12 h and, respectively, at 900�C/12h. Scanning electron micrographs together with the chemical elements mapping results were obtained. They were related to the previous results concerning the informations on the structure of the different phases found in this NiTiNb alloy: austenite, martensite and secondary phases, as well as some primary compounds [1,2]. Considering the size and shape of the complex precipitate particles of NiTiNb in the two differently heat treated samples, these were found responsible for some changes in the transformation temperatures [3] but the electrochemical corrosion behavior of the alloy seems to be influenced to a lesser extent by the heat treatments. Both samples exhibit good values of corrosion resistance, however S2 shows better values than S1. Thus lower transformation temperatures and a slightly better corrosion resistance make the Ni50Ti48Nb2 alloy annealed at 900�C/12h subsequently submitted to thermal cycling to be the right choice for producing couplings in the cryogenic industry.


Materials ◽  
2019 ◽  
Vol 12 (16) ◽  
pp. 2614 ◽  
Author(s):  
Xiuqing Fu ◽  
Wenke Ma ◽  
Shuanglu Duan ◽  
Qingqing Wang ◽  
Jinran Lin

In order to study the effect of nano-CeO2 particles doping on the electrochemical corrosion behavior of pure Ni-Fe-Co-P alloy coating, Ni-Fe-Co-P-CeO2 composite coating is prepared on the surface of 45 steel by scanning electrodeposition. The morphology, composition, and phase structure of the composite coating are analyzed by means of scanning electron microscope (SEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD). The corrosion behavior of the coatings with different concentrations of nano-CeO2 particles in 50 g/L NaCl solution is studied by Tafel polarization curve and electrochemical impedance spectroscopy. The corrosion mechanism is discussed. The experimental results show that the obtained Ni-Fe-Co-P-CeO2 composite coating is amorphous, and the addition of nano-CeO2 particles increases the mass fraction of P. With the increase of the concentration of nano-CeO2 particles in the plating solution, the surface flatness of the coating increases. The surface of Ni-Fe-Co-P-1 g/L CeO2 composite coating is uniform and dense, and its self-corrosion potential is the most positive; the corrosion current and corrosion rate are the smallest, and the charge transfer resistance is the largest, showing the best corrosion resistance.


2013 ◽  
Vol 341-342 ◽  
pp. 23-27
Author(s):  
Wei Cai ◽  
An Yun Li ◽  
Pian Xu ◽  
Yu Wu ◽  
Liang Chen ◽  
...  

Investigating the electrochemical corrosion behavior of Cu15Ni10Mn alloy in NaCl solution with different Cl concentration was studied by measuring open-circuit potential, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and cyclic voltammetry. The results show that as the Cl- concentration increase, the corrosion potentials of the alloy shifted negatively, corrosion currents increase, the corrosion process by electrochemical control change of diffusion control, and therefore the corrosion rates become faster. The presence of Cl- have effect on the dissolution mechanism and corrosion products of the alloy, when the concentration of Cl- is relatively low, a reducing peak current appears in the process of cyclic voltammetry retracing , when the Cl- concentration is higher, cyclic voltammetry flyback process does not appear to restore the current peak. This is mainly associated with the generation of corrosion product, when Cl- concentration is low, the corrosion product is Cu2(OH)3Cl (basic copper chloride) and other two copper ion salts, when the concentration of Cl-is higher, corrosion products are mainly Cu2(OH)3Cl (basic copper chloride).


Metals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1172
Author(s):  
Polina Metalnikov ◽  
Guy Ben-Hamu ◽  
Kwang Seon Shin ◽  
Amir Eliezer

Magnesium (Mg) alloys possess the lowest density among structural materials, and their application in the automotive and aircraft industries might enhance fuel efficiency. The mechanical properties can be improved by the addition of alloying elements. However, since Mg and its alloys are very susceptible to corrosion degradation, it is important to study the effect of these elements on the alloys’ corrosion behavior. In this study, 1 wt% of calcium (Ca) was added to wrought AM60 Mg alloy, and the electrochemical corrosion behavior of the alloys in alkaline solutions with and without Cl− ions was compared. The corrosion behavior was investigated by means of immersion tests, gravimetric measurements and potentiodynamic polarization (PDP); the characteristics of the oxide layer were studied by electrochemical impedance spectroscopy (EIS) and X-ray photoelectron spectroscopy (XPS). The addition of Ca resulted in precipitation of the ternary aluminum-rich (Mg-Al)2Ca phase. Scanning Kelvin probe force microscope (SKPFM) identified that this phase has a cathodic behavior relative to the α-Mg matrix; hence it can serve as additional sites for initiation of pitting corrosion. As a result, the corrosion resistance of wrought AM60 alloy with 1 wt% Ca addition deteriorated in a NaCl solution. However, in the absence of Cl− ions, alloying with Ca improves the corrosion resistance of wrought AM60 alloy due to the stabilization of the corrosion products layer. The effect of long-period immersion time on the corrosion behavior and alloy oxidation is discussed.


2008 ◽  
Vol 587-588 ◽  
pp. 355-359 ◽  
Author(s):  
Wislei R.R. Osório ◽  
Noé Cheung ◽  
Leonardo R. Garcia ◽  
Amauri Garcia

To address the increasing demand for high performance and high quality die castings, Zn-Al casting alloys have been developed, in particular for applications in the automotive industry. This family of alloys has good physical, mechanical and tribological properties and is commonly used as foundry alloys in a variety of applications. Particularly, the Zn-22 wt% Al eutectoid alloy is a classic commercial material and a fine-grained structure can be obtained by using a suitable heat treatment which can induce a superplastic behavior. On the other hand, this heat treatment can affect the corrosion behavior of such alloy. The present work focuses on the influence of as-cast and quenched microstructures of the Zn-22wt%Al eutectoid alloy on its electrochemical corrosion behavior. The typical microstructural patterns were examined by using optical microscopy techniques. In order to evaluate the corrosion behavior of such alloy, corrosion tests were performed in a 0.5 M NaCl solution at 25°C by using an electrochemical impedance spectroscopy (EIS) technique and potentiodynamic polarization curves. An equivalent circuit by using the ZView software was also used to provide quantitative support for the discussions and understanding of the electrochemical corrosion behavior. It was found that the heat-treated samples are more susceptible to the corrosion action than the as-cast alloy sample.


2013 ◽  
Vol 328 ◽  
pp. 882-885
Author(s):  
Cun Ren Ma ◽  
Hai Wei Lu ◽  
Guo Hua Lu ◽  
Wei Su ◽  
Tian Sheng Chen ◽  
...  

The electrochemical corrosion behavior of ultra-supercritical unit waterwall tube material in simulated solution of oxygenated treatment (OT) with different concentration of Cl- and SO42- at room temperature was investigated by electrochemical impedance spectroscopy and Tafel slopes. The results showed that the polarization resistance Rp values decreased and corrosion current density (icorr) increased with increasing Cl-/ SO42- concentration in solution. Corrosion potentials (Ecorr) decreased with increasing Cl-/ SO42- concentration in solution.


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